[PATCH] platform: Allow platforms to specify the size of tlb fifo

[Xiang W]

For some platforms with a particularly high number of harts, if the
tlb fifo is too small, it case harts to wait. Platforms should be
allowed to specify the size of the tlb fifo.

Signed-off-by: Xiang W <wxjstz at 126.com>
---
 include/sbi/sbi_platform.h | 29 +++++++++++++++++++++++++++++
 include/sbi/sbi_tlb.h      |  2 --
 lib/sbi/sbi_tlb.c          |  4 ++--
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/include/sbi/sbi_platform.h b/include/sbi/sbi_platform.h
index 3e9616f..5929042 100644
--- a/include/sbi/sbi_platform.h
+++ b/include/sbi/sbi_platform.h
@@ -39,6 +39,8 @@
 #define SBI_PLATFORM_FIRMWARE_CONTEXT_OFFSET (0x60 + __SIZEOF_POINTER__)
 /** Offset of hart_index2id in struct sbi_platform */
 #define SBI_PLATFORM_HART_INDEX2ID_OFFSET (0x60 + (__SIZEOF_POINTER__ * 2))
+/** Offset of tlb_fifo_num_entries in struct sbi_platform */
+#define SBI_PLARFORM_TLB_FIFO_NUM_ENTRIES (0x60 + (__SIZEOF_POINTER__ * 3))
 
 #define SBI_PLATFORM_TLB_RANGE_FLUSH_LIMIT_DEFAULT		(1UL << 12)
 
@@ -192,6 +194,15 @@ struct sbi_platform {
 	 * 2. HART id < SBI_HARTMASK_MAX_BITS
 	 */
 	const u32 *hart_index2id;
+
+	/**
+	 * For some systems with too many harts, too small tlb fifo
+	 * may cause harts to wait. For such systems, this number
+	 * can be increased.
+	 *
+	 * This value can be change in platform_override->fw_init
+	*/
+	u32 tlb_fifo_num_entries;
 };
 
 /**
@@ -243,6 +254,11 @@ _Static_assert(
 		== SBI_PLATFORM_HART_INDEX2ID_OFFSET,
 	"struct sbi_platform definition has changed, please redefine "
 	"SBI_PLATFORM_HART_INDEX2ID_OFFSET");
+_Static_assert(
+	offsetof(struct sbi_platform, tlb_fifo_num_entries)
+		== SBI_PLARFORM_TLB_FIFO_NUM_ENTRIES,
+	"struct sbi_platform definition has changed, please redefine "
+	"SBI_PLARFORM_TLB_FIFO_NUM_ENTRIES");
 
 /** Get pointer to sbi_platform for sbi_scratch pointer */
 #define sbi_platform_ptr(__s) \
@@ -370,6 +386,19 @@ static inline bool sbi_platform_hart_invalid(const struct sbi_platform *plat,
 		return true;
 	return false;
 }
+/**
+ * Get number of tlb fifo entries
+ *
+ * @param plat pointer to struct sbi_platform
+ *
+ * @return number of tlb fifo entries
+*/
+static inline u32 sbi_platform_tlb_fifo_num_entries(const struct sbi_platform *plat)
+{
+	if(plat && plat->tlb_fifo_num_entries)
+		return plat->tlb_fifo_num_entries;
+	return 8;
+}
 
 /**
  * Check whether given HART is allowed to do cold boot
diff --git a/include/sbi/sbi_tlb.h b/include/sbi/sbi_tlb.h
index 48f1962..55dcab0 100644
--- a/include/sbi/sbi_tlb.h
+++ b/include/sbi/sbi_tlb.h
@@ -20,8 +20,6 @@
 
 /* clang-format on */
 
-#define SBI_TLB_FIFO_NUM_ENTRIES		8
-
 struct sbi_scratch;
 
 struct sbi_tlb_info {
diff --git a/lib/sbi/sbi_tlb.c b/lib/sbi/sbi_tlb.c
index 26a87f3..92648da 100644
--- a/lib/sbi/sbi_tlb.c
+++ b/lib/sbi/sbi_tlb.c
@@ -422,7 +422,7 @@ int sbi_tlb_init(struct sbi_scratch *scratch, bool cold_boot)
 			return SBI_ENOMEM;
 		}
 		tlb_fifo_mem_off = sbi_scratch_alloc_offset(
-				SBI_TLB_FIFO_NUM_ENTRIES * SBI_TLB_INFO_SIZE);
+				sbi_platform_tlb_fifo_num_entries(plat) * SBI_TLB_INFO_SIZE);
 		if (!tlb_fifo_mem_off) {
 			sbi_scratch_free_offset(tlb_fifo_off);
 			sbi_scratch_free_offset(tlb_sync_off);
@@ -453,7 +453,7 @@ int sbi_tlb_init(struct sbi_scratch *scratch, bool cold_boot)
 	ATOMIC_INIT(tlb_sync, 0);
 
 	sbi_fifo_init(tlb_q, tlb_mem,
-		      SBI_TLB_FIFO_NUM_ENTRIES, SBI_TLB_INFO_SIZE);
+		      sbi_platform_tlb_fifo_num_entries(plat), SBI_TLB_INFO_SIZE);
 
 	return 0;
 }
-- 
2.40.1